Fluoropolymers are important items of commerce being used in many applications. For some applications such as for making coatings or foams, sealing of porous substances and encapsulation it is desirable to dissolve the fluoropolymer in a solvent. However, many of the solvents for fluoropolymers have various drawbacks, such as being greenhouse gases, high flammability, toxicity, etc. Liquid or supercritical carbon dioxide is a relatively benign solvent which is known to dissolve some fluoropolymers. However typically these polymers have been/must be dissolved at relatively high temperatures and pressures. This necessitates the use of very expensive equipment and has limited the practical utility of CO.sub.2 as a solvent.
U.S. Pat. No. 5,496,901 describes the "solution" polymerization of a wide variety of fluoropolymers in liquid or supercritical CO.sub.2. No mention is made of dissolving the specific polymers used under the conditions described herein.
U.S. Pat. No. 5,530,049 describes the dissolution of high melting point fluoropolymers at temperatures and pressures higher than used herein.
U.S. Pat. No. 5,618,894 describes a process for making fluoropolymers with stable end groups in the presence of liquid or supercritical carbon dioxide. No mention is made of criteria for polymer solubility in CO.sub.2.